Some capacitors are made with dielectric material sandwiched between a top and a bottom electrode in an integrated parallel-plate overlay capacitor structure. In such a structure, the bottom electrode thickness can be constrained by the dielectric thickness. The losses in the thin bottom electrodes can limit the overall high frequency quality factor of such capacitors. Additionally, the higher electrical field between the top and bottom electrodes at the edge of the crossover can create premature breakdown under the application of high bias voltages or large AC signals to the capacitor. As the frequency increases, electromagnetic waves travel towards the surface of the circuits, making the surface properties, deposition techniques and design critical. As the surface wave velocity propagates throughout the surface of the capacitor, the waves can be slowed due to the field shortening effect. The degree of the effect is typically dependent on the geometry and pattern of the top metallization.
In a standard 0603 surface mount package, the size of active area of the capacitor is just 150 micrometers square. An 0201 surface mount package would be 250 micrometers by 500 micrometers and a wire bonded package using this technology would be as small as 60 micrometers by 60 micrometers.